First-stage nozzles of gas turbines, which are the first elements after the combustion chamber, encounter
hot gases from the combustion process and have the task of directing the fluid path and increasing
the velocity of combustion products. This paper reports on the incidence and failure of the
first-stage nozzles of a gas turbine in September 2013 at a seaside pump-house located in the SouthWest
of Iran. The nozzle was made of nickel-based superalloy Nimonic105. Due to nozzle failure, the
turbine was damaged severely. The cause of nozzle failure was investigated. The results of visual inspection,
XRD analysis of deposits on the blade airfoil, SEM images and EDAX analysis showed the
characteristics of hot corrosion. Finite-element analysis (FEM) revealed that the cause of blade
trailing edge failure was thermal stress leading to thermal fatigue, which accelerated nozzle blade
failure in addition to the hot corrosion